Steam generator



March 6, 1928. 1,661,543

H. A. NICHOLSON s'rmm esmmgwon Filed Jun 24. 9 9. 6 Sheets-Sheet 1 INVENTOR March 6, 1928. 1,661,543

H. A. NICHOLSON STEAM GENERATOR Filed June 24. 1919 6 Sheets-Swat 2 11a 1- i 700 INVENTOR "5:2"

March 6, 1928. 1,661,543

H. A. NICHOLSON STEAM GENERATOR Filed June 24, 1919 s Sheets-Sheet 3 INVENTOR EI/I ATTORNEY March 6, 1928. 1,661,543

H. A. NICHOLSON STEAM GENERATOR Filed June 24, 1919 s Sheets-Sheet 4 INVENTOR ATTORNEY March 6, 1928. 1,661,543

H. A. NICHOLSON STEAM GENERATOR Filed June 24, 1919 .A 6 Sheets-Sheet 5 INVENTQR @xm MW March 6, 1928. 1,661,543

' H. A. NICHOLSON STEAM GENERATOR Patented Mar. 6, 1928.

UNITED STATES PATENT OFFICE.

HENRY A. NICHOLSON, OF ARKLES BAY, AUCKLAND,

' ERNEST A. CRAIG- 01 AUCKLAND, NEW ZEALAND. i

NEW ZEALAND, ASSIGNOR TO scream GENERATOR.

Application filed J'une 2,4, 1919. Serial No. 303,898,

This invention relates to steam-generators; being directed partly to the type of generator disclosed in my pending application N 0. 284,657, filed March 24, 1919, and

5 partly to improvements in means for generating steamby the combustion of oil, both in the type of generator set forth in said application and also in other types of generators and boilers, etc. In said application is disclosed anoncirculatory generator in the nature of a water pipe or main, into one end of which water is forced under high pressure by a pump, and at the other end of which the Water is converted and delivered as steam or as steam and water, having been heated constantly while advancing only once and in the same direction through said inainthe delivery being into a steam 2i} drum mounted in the furnace uptake, whereby the residuum (it any) of Water is converted into steam; The main is also shown as divided at one portion into a grid,

. L by which the stream is split up into fine divisions for more intimate exposure to the heat; a suitable Water drum being also in cluded in said main, for providing a reserve body of highly heated fluid under high pressure. At the terminal of the water main or system, the fluid is delivered in the form of steam, or a mixture of Water and steam, through a converting device.

There is illustrated in the present draw ings a method of generating steam by means of a single-direction Water-flow main or sys tem, by the use of oil as. a fuel. The fuel is shown as consumed in a dame chamber beneath a water grid, but preferably separated therefrom by a bridge; and the water main 4h preferably includes a coil imbedded in saidbridge, to be subjected to heat both above and below. There is also shown imbedded in the trout Wall ot' the grid chamber, a vertical coil consistingof a zigzag section of 4 the fluid main, through which the fluid courses from top to bottom, so that it res ceives the greatest heat as it reaches the bottom; and preferably from this point the fluid courses to and .fro around three sides of the flame chamber, in a zigzag course, be

fore entering the water-reserve-drums. Two

of these drums areprovided to augment the capacity of the system and increase the safeguard against trouble.

The oil-burner, of which as mgny may be employed as required, four being illustrated,

embodies a substantial departure from the prevailing method of injecting oil into the combustion-chamber in a boiler in the form of a sheetorspray of oil, forcing a powerful air blast through-the flame chamber in an attempt to burn the-oil as rapidly as posslbl, and result-ingin the loss of many heat units through the escape of unconsumed fuel through the smoke pipe. An object of certain of the present improvements is to provide for an increase in the length of the life of the fiame, or, in other Words, to extend the time used for combustion of each atom of the fuel, so that it will be fully consumed while coursing through the generator. ll aim to produce a rolling flame or-flame cloud, which will iloat at moderate speed through the flame chamber and up around the grid, to deliver a maximum of heat to the Water. At the burner ll force into the furnace a constant stream of air from a pump or blower, this stream having great volume but: relatively low rate of dew; and it enters the furnace through an inlet that flares on its inner or furnace side, Withthe sheet that a large volume of air is supplied at relatively low speed, Into this air stream, at the point where the inlet begins to flare, the fuel oil is fed under pressure through a spreader or spray having the cheat of atomilzing the oil. To do this, the oil is caused to escape trom'a jet which has a flaring month, said mouth plug, which is held closed by a spring. The force of the feed oil will overcome the power of the spring, and a minute opening will be termed, that is, the cone plug will separate very slightly from the flaring mouth of the jet, making only space enough for the oil to escape in an extremely fine or atomized condition, into the inflowing stream of air, "at the place of highest pressure of the latter. From this point of oilsupply, the air .begins to expand in volume, as well as to advance at, lower speed, and the air and fuel mix to form a mist or cloud, ada ted to float slowly through the flame oha-m r and up through the Water-tube grid; The fine atomizing of the fuel in this airsupply insures its perfect combustion, and the progress of the mixture through the furnace is sufiiciently slow to afford time for the completion of the combustion. Hence asubstantially larger number of heat units is utilized being closed by a conical from the fuel than has heretofore been found practicable.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a sectional elevation taken from front to rear of an oil-burning steamgenerator embodying the present improvements in one form.

Figure 2 is an enlarged sectional detail of the oil and air feed to the furnace.

Figure 3 is a plan of the generator.

Figure 4 is a sectional rear elevation of the generator, to show the zigzagging portion of the main at the front of the grid chamber, as well as the zigzag box portion of the main surrounding the flame chamber, and in the bridge over the flame chamber or furnace. This also shows the nozzles of the four fuel burners.

Figure 5 is a front sectional elevation, showing a section of the water grid, and also illustrating a part of the zigzag box course of the water main around the furnace.

Figure 6 is a sectional plan showing the zigzag course of the main through the bridge over the furnace, and also indicating by dotted lines the boxed zigzag portion of the main around the furnace.

Figure 7 is a dia ram of the water main and subdivisions 3,11% appurtenances.

Figure 8 shows the preferred manner of connecting the fire-box bridge-coil in the system.

A force pump 10 is connected to one end of a main which is designated generally as 11, and which comprises a riser 12, connected by an elbow 13 and a backcheck valve 14 to the uppermost of a set of horizontal pipes 15 of the same diameter as the main 11, and forming a vertically arranged coil or zigzag section of the main, these pipes being preferably cast in one piece and connected at alternate ends by unions in the form of U-shaped fittings 16, Figure 4, said fittings being retained by straps and nuts 17, which permit of easy removal of the couplings for inspection, cleaning and replacement.

This zigzag set of pipes is embedded in the front wall 18 of thegenerator, which is heated by the flames and gases rising from the furnace or flame chamber 19, so as to give a preliminary heating to the water as it is forced through the generator by the pump 10.

The lowermostof the couplings 16 is a special fitting, being connected by an elbow 20, Figures 4 and 6, to the first or righthand one of a set of horizontal pipes 21 overlying the flame chamber or furnace 19, and embedded in a bridge 22 of bricks, blocks or plates of refractory material, which extends fron the front wall of the flame chamber nearly to the back wall thereof, leaving an opening 23 for the egress of flames and gases at the back of the flame-chamber. These pipes are connected to form a horizontal zigzag course by means of unions or couplings 24 cast in front and rear horizontal headers 25 and 26, also embedded in the material of the bridge, the front header having clean-out openings for all the pipes in the set, these openings closed by screw plugs 37. Before assing into the reserve drums presently to be described, the water receives a high degree of heat from its passage through this bridge coil.

After traversing said bridge coil, the fluid is led to and fro around the sides and back of the flame-chamber, for further heating. The connection between the bridge coil and the firebox coil is in the form of an inclined U-fitting 28, Figures 4 and 6. This joins with the topmost pipe 29 in a set at the side of the fire-box. Pipe 29 is joined by an elbow 30, Figure 6, to the topmost pipe in a set 31 at the rear of the fire-box, the latter communicating by an elbow 32 to the top pipe in a tier 33 at t e right-hand side of the box. At the front end of this topmost pipe 33, it is connected by a U-connection 34 to the next underlying pipe in set 33, which by means of elbows communicates with corresponding pipes in the rear and left-hand sets 31, 29. Some of these elbow and U-joints may be formed in headers 35, 36 placed at the rear corners of the fire-box and partly or wholly encased in the walls there of. In the front may be fitted clean-out screw plugs 37, Figure 1, and in the rear headers may be similar plugs 38, Figure 6; one of the features of the invention being the provision of facilities for readily cleaning out pipes and tubes that are arranged to perform the described functions. It will be seen that after zigzagging through the bridge coil, the fluid zigzags through the threesection fire-box coil, and receives additional heat, without, however, having the effect of unduly cooling or shortening the flames, since the material of the fire-box walls and the bridge may be refractory and heat-conducting, and adapted to become incandescent, to presenta highly heated surface to the flames, while heating the embedded coils. It will be noted that the two middle ipes of the set of four in the left-hand side wall (or the right-hand at Figure 4, which is a .rear view) may be joined by a. U-passage 39 provided in the header at this corner.

From the lowermost pipe in the ri hthand section 33 of the fire-box coil, the uid (which has been radually heated and finally brought to a high degree of heat at the hottest part of the generator) is led out through a pipe 40, elbow 41 and riser 42, Figures 3, 4, 6, the upper end whereof is connected to horizontal ipe 43, Figure 3, leading b elbows 44 an 45 to a hot water reserve diam 46, mounted horizontally in the top of the I generator, to be heated by the escaping gases; this being the middle of the three drums shown. For additional safeguard there is preferably employed a second reserve water drum 47, in front of thefirst; all three drums mounted upon bridgework 48 at the top of the generator, Figure 1, and beneath a dome 49, passages being left for free circulation of hot gases all around the drums as they rise to the smoke pipe 50 erected upon the middle of the dome.

'Said reserve water drum 46 is directly con nected to said auxiliary reserve drum 47, the fluid flowing from, the upper part of the I first through a diagonal connection 51 to the lower part of the auxiliary drum 47, the latter having in the upper portions of its ends outlets 52. ,These outlets are in the upper portions of the drums, to insure against the collection of steam in the latter. li steam should form in either drum, it would rise to the top, and so he forced out of the drum ahead of the water. Hence there is maintained a large reserve of water heated above the boiling point From the ends of the auxiliary reserve drum 47 the heated fluid is led through the fittings 52 andelbows 53 down through ver tical pipes 54; to join the forward ends of distributing headers 55, 56, one at either side of the combustion chamber, 'lhese headers open into vertical grid sections or coils, each comprising opposite vertical side headers 57 and 58,. and each also comprising a vertical series of horizontal tubes 5% opening into said side headers, the latter having therein suitable ll-connections 59 so that each section is a zigzag coil through which the fluid advances down from the distributing header on one side to the collecting header on the opposite side, there being two of these collooting headers 60 and 6i. Each grid section or coil is detachable from the generator, and provided with clean-out openings having plugs 62, and having flanged connections 63 at diagonally opposite corners with the 'headers, and adjustable supports v6d at the remaining two corners, lill as set forth in my said application. By these small tube coils is formed a grid, up through which course the flames and hot gases to the top of the generaton the fluid being divided up hy the tuhes into small streams, to expose it more intimately, to the heroes and gases. "rte final heating of the fluid occurs at the lowest portion of the grid, nearest to the fire box, Where the generator is hottest; and at this stage the fluid is heated very far above 212 degrees; andis under high pres sure. i i

From the collecting headers 60, 61 the fluid, heated to a high temperature, advances through elbows 65, risers '66 and elbows 67 to forwardly-extending horizontal pipes 68, in which are provided pressure-redueingjets 69 and 7 0, opening into the ends of a steam drum 71 laced in rear of the water reserve drums. y these jets or valves 69, 70, which are of small diameter in comparison with the main pipes 67 and 68, the pressure in the fluid main is kept above the pressure in the steam drum.

From an outlet 72 at the top of the steam drum leads a service pipe 73 provided with a stop valve 74, and also an elbow 7 5 carryinga service safety valve 76. A second safety valve 77, set at say 100 pounds higher pressure than valve 76, may be provided at the top of the auxiliary water reserve drum 4.7. Under ordinary conditions, the pressure in the. generator will-not get above the point at which the service safety valve 7 6 is set; but if the emergency valve 7 7 should blow ofi while the service valve 76 remains closed, the attendant will be warned thereby that fluid is not flowing freely through the grid, or that some other trouble has developed.

N3 the generator is being warmed up,

the pump lfl is still, but there is a certain circulation of water in the main, including the grid, which prevents overheating of the tubes or main at any point. This circulation is automatic, being due to the heating of the water, which as it gets warm rises to the top ol'the generator, and then as it cools descends to the bottom, to become re-heated and rise again, To secure this flow of water while warming up the generator, valves 78 and 79 are opened in pipes 80 and 81, to open counication between the steam drum which may now he nearly filled with water) and the water reserve drum 46. Valves 82 and 82 in pipe 83 are also opened, to effect direct counication between reserve water drum 46 and the standing coil 15 at, the front of the combustion chamber, the fluid assing down said coil 15 and thence to the ridge coil 21 and the fire-box coil 29, 31, 33. ll valve 84: may also be opened, to open up a tree communication between the auxiliary reserve drum 47 through pipe 43 to Jnain 42., .lsthe water warms, it will rise through the grid and flow through the upper headare and pipes to the drums, and will descend through the risers to the bottom of the grid, in which. it will rise again to the drums, thus maintaining the circulation.

this way the water will continue to heat and circulate until steam is present in the steam drum, whereu on,the force pump is converted into steam any residuum of water that may enter the steam-drum.

Preferably the bridge-coil 21 should be included in the main between the grid and the steam drum, Figure 8, so that the fluid may be exposed to the greatest heat just as it is about to be delivered to the steam drum. For this purpose the two bottom or collecting headers may be connected by a cross pipe 85, from which may lead a pipe 86 comprising elbows or fittings 87 and 88, to one end of the bridge-coil, at 89; a pipe 90 leading from the other end of the bridge-coil and being connected through elbows or fittings 91 and 92 to a cross main 93, which.at its ends may be connected by risers 66 to the elbows (57 leading to the steam drum. The lower end of the vertical front coil may be connected directly by a duct or fitting 95 to the upper end of one side of the box coil.

Into the front of the fire-box 19 may open four burners 100, one of which will be described in detail. The fuel oil is forced by a pump 101 into a cross main 102, from which branches 103 extend to the burners 100, each branch terminating in a diagonal pipe 104, Figure 1, or an elbow 105, Figure 2, opening into a chamber 106 having an outlet 107 of small diameter and flaring outwardly; this outlet being formed at the apex of a conical shell 108 located at the outer end of an orifice 109 in the front wall of the fire-box. The oil is forced through the outlet 107 and through said opening 109 into the fire-box or flame-chamber 19. Said outlet 107 is normally closed by means of a plug 110, which may be of conical form to fit the flaring outlet, and may be provided with a guiding stem 111, fitting in a guide-hole 112 in a burner plate 113 arranged vertically upon the front wall of the furnace and containin the oil inlet 105. This stem may be pro onged and surrounded by a compression spring 114, which is compressed between a head 115, carried upon the outer end of the stem, and the plate 113. The spring holds the outlet closed until its resistance is overcome by the pressure of the oil as it is forced by the pump 101; this oil pressure sufiicing to make a minute opening between the plug 110 and the mouth 107 of the burner, permitting the oil to escape in the form of a conical sheet or spray in atomized condition; the opening in the front wall of the furnace flaring inwardly at 116 to permit this spraying of the oil without striking the furnace wall edges, and to favor the formation of a slowly advancing flame cloud.

As the oil emerges in this atomized condition, it mixes with a current of air derived from a blower 117, which communicates with one end of an air box 118 at the front of the fire box, said air box extending the width of the furnace, andhaving where the pressure of the latter is greatest, I

and from this point the air, entering through the flaring orifice 116, is reduced somewhat in pressure; and the mixed air and fuel burn in a rolling flame, the time of combustion being prolonged, and the flame passing back through the fire box and up through opening 120 in the top, back of the bridge, and up through the grid.

Within the grid chamber may be arranged bafile plates 121 to prolong the course of the flame and gas through the chamber, and afford more opportunity for the fluid to take up the heat; these bafiie plates bein placed between alternate rows of grid tu es, and being arranged so as to leave flameand gas openings or passages at the front and back of the grid chamber alternately, so that the flames pursue a zigzag course.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. A steam generating apparatus comprising a combustion chamber with a continuous coil of large diameter extending around the sides thereof, a bridge above the chamber with a large coil extending back and fort-h therethrough and connected at one end with the combustion chamber coil, coils of pipe of smaller diameter extending downwardly and terminating just above the bridge, a water drum between the large and small coils and a steam drum into which the smaller coils deliver, said coils being all connected at their entrance ends with the lar e combustion chamber and bridge coils, an means to force fluid only once first through the lar e coils, and thence through the small coils into the steam drum.

2. In a steam generating apparatus, a combustion chamber, a bridge extending over the top from the front to nearly the back of the combustion chamber, a preheating zig-za' coil embedded in the bridge, a heating chamber above the combustion chamber, a pre-heating ziz-zag coil in front of the heating chamber and in communication with the coil in the bridge, a series of smaller coils in the heating chamber, a water drum and a header interposed between the preheating coils and the smaller coils in the heating chamber, the water drum being so connected to the coils as to prevent accumulation of steam therein, and a pump for forcing fluid 'firstthrough the preheating coils to the drum and from the drum through the header to the small coils in the heating chamber, and a steam drum connected to the outlet ends of the small coils.

3. In a steam generating apparatus, a combustion chamber, a bridge extending over the top from the front to nearly the back of the combustion chamber, a preheating zig-zag coil embedded in the bridge, a heating chamber above the combustion chamber, a preheating zig-zag coil in front of the heating chamber and extending from top to bottom of the heating chamber and in communication with the coil in the bridge, a series of smaller coils in the heating chamber, a water drum and a header interposed between the preheating coils and the smaller coils in the heating chamber, the

' water drum being so connected to the coils as to prevent accumulation of steam therein, and a pump for forcing fluid first through the preheating coils to the drum and from the drum through the header to the small coils in the heating chamber, and a steam drum connected to the outlet ends of the small coils with a pressure reducer between the small coils and the steam drum.

4. A steam generator comprising a flame chamber, preheating coils and coils with smaller diameter for exposing the fluid in small streams to the heat, a plurality o;t was ter drums between the preheating coils and smaller coils, said drums being normally in communication with the inlets only of the smaller coils, means for connecting the drums to the outlets of the smaller coils to allow circulation in either direction through the smaller coils and drums with means for forcing fluid in a single direction through said coils and drums.

5. A steam generator comprising a combustion chamber surrounded with compara tively large preheating coils, a heating chamber, a plurality of small heating coils extending vertically through vthe heating chamber, a plurality of water drums and a steam drum in the heating chamber above the small coils, the coils and drums being normally so connected that fluid may be forced once only in a single direction through the preheating coils, the drums and the heating coils, said steam drum connected to the ends of the heating coils and normally disconnected from the water drum with means to connect the steam drum and water drums to allow circulation in either direction through the system.

6. A steam generator comprising a combustion chamber surrounded with comparatively large preheating coils, a heating chamber, a bridge having a preheat-ing coil embedded therein and extending between said chambers, a plurality of small heating coils extending vertically through the heating chamber, a plurality of water drums and a steam drum in the heating chamber above the small coils, the coils and drums being normally so connected that fluid may be forced once only in a single direction through the preheating the heating coils, said steam drum connected to the ends of the heating coils and normally disconnected from the water drum with means to connect the steam drum and water drums to allow circulation in either direction through the system.

HENRY A. NICHOLSON.

coils, the drums and 

